(a) Field of Invention
This invention relates to tricyclic alkylamine compounds, to their preparation and use, and to intermediates for their preparation.
More specifically, this invention relates to tricyclic alkylamine derivatives in which the tricyclic portion thereof is characterized by having an indole portion fused to a cyclopentane, cyclohexane or cycloheptane ring. Still more specifically, the compounds of this invention are characterized as derivatives of one of the following tricyclic ring systems: ##STR1## (a) 1,2,3,4-tetrahydrocyclopent[b]indole, ##STR2## (b) 1,2,3,4-tetrahydrocarbazole, or ##STR3## (c) 5,6,7,8,9,10-hexahydrocyclohept[b]indole, in which the carbon atom bearing the alkylamine residue is carbon atom 3, 1 and 6 in the respective ring system. In each case the carbon atom bearing the alkyl amine is substituted further with a lower alkyl.
(B) Prior Art
Apparently, the closest prior art to the compounds of the present invention is the recent German Offenlegungsschrift No. 2,263,682, published July 4, 1973, corresponding to U.S. Pat. No. 3,859,304, and which describes a series of carbazole-1-alkylamines. Although the latter compounds are claimed to be antidepressive agents, the compounds of the present invention are distinguished readily from these prior art compounds by their structural arrangement and pharmacologic properties. More particularly, they are distinguished by their increase in antidepressant potency and improved therapeutic ratio and by the fact that in the compounds of this invention the carbon atom bearing the alkylamine is fully substituted whereas in the prior art compounds the corresponding carbon atom is not.
Other prior art, although somewhat further removed, is exemplified by U.S. Pat. No. 3,592,824, issued July 13, 1971 and U.S. Pat. No. 3,634,420, issued Jan. 11, 1972. Although these examples of prior art disclose carbazolealkylamines, the fact that the disclosed compounds bear no substituent whatsoever at position I readily distinguishes them from the compounds of the present invention.